The Alzheimer's Association's annual count reflects the aging population. [Photo credit: Adobe Stock][/caption]By Beth Baker for Next Avenue

The estimated number of Americans with Alzheimer’s disease and other dementias has risen to 5.7 million, from 5.5 million in 2017, according to a report released today by the Alzheimer’s Association.

That’s an increase of roughly 3.6 percent and largely reflects the aging of the boomer generation.

By 2025, the 2018 Alzheimer’s Disease Facts and Figures report projects, 7.1 million Americans aged 65 and older will have Alzheimer’s, and by 2050, some 13.8 million.

Dementia from causes other than Alzheimer’s make up anywhere from 15 to 40 percent of cases. These include strokes (vascular dementia), Lewy bodies (abnormal clumps of protein in the brain), frontotemporal lobar degeneration and Parkinson’s disease. Complicating the picture, many people have dementia from both Alzheimer’s and other causes, especially vascular.

Estimates Are Challenging

Accurate counting of Alzheimer’s cases is difficult, said Ron Brookmeyer, professor of biostatistics at the UCLA Fielding School of Public Health, who was not involved with the new report. There is no national surveillance of the disease and the line between what is called “mild cognitive impairment” (sometimes the first stage of Alzheimer’s) and dementia is fuzzy.

“Different researchers can use different thresholds, and that can really impact the numbers,” Brookmeyer said. Regardless, “the projections [in the new report] that by 2050, we’re going to be seeing over a two-and-a-half-fold increase in Alzheimer’s dementia prevalence is pretty accurate, and that is really driven by the aging of the population.”

In addition to age, having a parent or sibling with the disease or having a gene variant called APOE-e4 are immutable risk factors. Other factors are modifiable and may protect cognitive health — exercising, eating a heart-healthy diet and remaining mentally and socially active. Having more years of education is also associated with reduced risk of dementia.

More Women, Blacks and Hispanics With Alzheimer’s

Two-thirds of Alzheimer’s patients are women. This may be in part because women live longer than men. Researchers are coming to consensus though “that the age-specific risk for Alzheimer’s is probably the same between men and women,” said Keith Fargo, director of scientific programs and outreach for the Alzheimer’s Association. In other words, an 85-year-old has the same risk, regardless of his or her sex.

African-Americans and Hispanics are at higher risk than whites, and Asian-Americans are at lower risk although data are skimpier for this group. The report finds these differences are likely due to varying health (including diabetes and heart disease), lifestyle and socioeconomic risk among the groups.

A $1 Trillion Price Tag for Dementia Care?

Care for patients with all types of dementia costs $277 billion, two-thirds of it borne by taxpayers. That figure represents “hard costs,” said Fargo, including Medicare, Medicaid, out-of-pocket spending — mostly for costly nursing homes — and private insurance. Half of the people living in nursing homes have dementia.

The report projects that dementia-related spending on care will grow to over $1 trillion by 2050, if trends continue.

In addition, the report noted, family members and other unpaid caregivers contributed 18.4 billion hours in care, at an estimated value of $232 billion, in 2017.

The number of deaths from Alzheimer’s disease increased by 123 percent between 2000 and 2015, the report found, unlike other major causes of death, which are declining.

“Some of that increase is probably driven by physicians doing a better job of diagnosing Alzheimer’s disease and then listing it on the death certificate,” said Fargo. “It’s probably also driven by the increase in the number of people who have this disease and by decreases in deaths from other causes. Maybe 30 years ago, if you had heart disease, that would get you before you got Alzheimer’s.”

Of the top 10 causes of death in the U.S., Alzheimer’s is the only one for which there is no prevention or cure or even a way to slow it down.

From 2002 to 2012, 244 drugs to treat Alzheimer’s made it to clinical trials and only one (memantine) was approved by the Food and Drug Administration. That brought to five the number of available medications that can temporarily treat symptoms for some patients, the report noted.

Scientific Understanding Deepens

Despite disappointments, considerable progress has been made in understanding the disease process. Researchers now believe that there is a “preclinical stage” of the disease lasting 20 years or more when there are pathological changes in the brain that may cause either no symptoms or mild cognitive impairment.

These neurological changes, such as the build-up of beta-amyloid plaque and protein tau in the brain — called biological markers of Alzheimer’s disease — can now be measured through PET scans or by analyzing spinal fluid.

Finding measurable biomarkers is critically important, Fargo explained, just as measuring blood glucose is fundamental to diagnosing and treating diabetes. By positively identifying that a patient has amyloid plaque in the brain, for example, potential drugs can be tested and measured to learn if they effectively reduce the plaque, even before the patient has symptoms.

Today, such biomarker testing is used mostly by researchers. Fargo said it is not appropriate for most individuals and is not covered by Medicare or private health insurance. Scientists are hoping to develop less expensive, less invasive tests to better target therapies to those most at risk of Alzheimer’s and to do so before the symptoms have begun.

“Now that we’re beginning to understand the pathogenesis of the disease, there’s an excitement in the field for developing preventions,” said Brookmeyer. “If we can delay the onset for just a couple of years, that would have a huge public health impact — on quality of life, on caregivers and on the cost of dealing with this problem.”

Glimmers of Hope

Although the trend is worrisome, dementia is neither inevitable nor a normal part of aging. Nine out of 10 people who are 65 or over do not have Alzheimer’s.

“It’s a specific brain disease,” said Fargo. “It is true that the older you are, the more at risk you are. But even in those 85 or older, one in three will get the disease. Like any disease, it’s [surmountable]. The hope is in the research.”

One ray of hope came in 2016, when researchers found that the incidence of dementia (the number of new cases of dementia of all types) in participants in the long-term Framingham Heart Study had decreased. On average, since 1977 there was a 20 percent decline in the incidence of dementia per decade in this population.

“We have seen in many western countries in Europe and to some degree in Canada and the U.S. that the incidence rate of new cases of dementia may be decreasing,” said Fargo.

That said, Fargo added, “These are relatively homogenous populations. We know there are fewer strokes and fewer heart attacks [than in previous years]. That’s probably resulting in reduced vascular dementia [as opposed to Alzheimer’s]. But it is reason to hope.”

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